摘要:

All-trans-[11-3H]retinyl acetate was injected directly into the testes of young rats and testicular and liver metabolites were analyzed by HPLC at 6, 24 and 72 h post injection. All-trans-retinyl acetate was hydrolyzed to retinol and further metabolized to polar compounds and a trace of retinoic acid, or reesterified to various retinyl esters including retinyl palmitate and retinyl stearate. Thus, retinyl ester hydrolyzing and esterifying enzymes are present in the testes of young rats. Eleven, twelve and ten radioactive peaks were observed at 6, 24 and 72 h, respectively. The amount of radioactivity in retinyl palmitate and retinyl stearate increased with time and reached 24 and 4%, respectively, by 72 h. Although retinol predominated, retinyl palmitate was the major esterified form in testis. The amount of radioactivity in retinol and retinyl acetate decreased with time and increased in unidentified metabolites and retinyl esters. An insignificant amount of radioactivity was found in liver. We conclude from these results that some vitamin A is stored/accumulated in the testes as retinyl esters in order to support the process of spermatogenesis and other physiological functions and that the retinol esterifying enzyme is quite active in the testes of young rats.

ISSN:0250-6807    

DOI:10.1159/000177170

出版商:S. Karger AG    

年代:1986

数据来源: Karger

ISSN:0250-6807    

DOI:10.1159/000177228

出版商:S. Karger AG    

年代:1986

数据来源: Karger

摘要:

The biological activity of two fluorinated analogs of 1,25(OH)2D3 was compared with 1,25(OH)2D3 in various vitamin D assays. The effect of 24,24-F2-1,25(OH)2D3 on plasma calcium, bone weight and duodenal calcium binding protein in chicken, on calcium excretion via egg shell in Japanese quails and on mobilization of calcium from the bone in rats was twice as high as the effect of the most potent naturally occurring vitamin D3 metabolite 1,25(OH)2D3. In contrast, 24R-F-1,25(OH)2D3 has less than 50% of the potency of 1,25(OH)2D3. Due to the wider therapeutic dosage range, this compound might be of clinical value.

ISSN:0250-6807    

DOI:10.1159/000177171

出版商:S. Karger AG    

年代:1986

数据来源: Karger

ISSN:0250-6807    

DOI:10.1159/000177230

出版商:S. Karger AG    

年代:1986

数据来源: Karger

摘要:

The changes in the absolute and relative contents of α- and ĸ-caseins, lactoferrin, α-lactalbumin, serum albumin and lysozyme in human milk have been studied through the period of lactation. Protein fractions of 209 samples were analyzed by a discontinuous poly-acrylamide gel electrophoresis method, β- and ĸ -caseins decreased from colostrum to mature milk although their relative percentages remained constant. They accounted for 12–15 and 9–13% of the total protein in human milk, respectively. Lactoferrin decreased in absolute and relative amounts with advancing lactation. This protein represented 32–19% of the human milk proteins. α-Lactalbumin slightly decreased from colostrum to transitional milk but there was an increase in mature milk by 16–30 days. The percentages of this protein in colostrum and mature milk were approximately 23 and 30%, respectively. Serum albumin also decreased with advancing lactation, but the differences between transitional and mature milk were not statistically significant. Lysozyme increased from colostrum to mature milk both in relative and absolute amounts. Colostrum contained about 262 µg/ml, and mature milk 1,246 µg/ml, representing 1.5 and 12.1% of tota

ISSN:0250-6807    

DOI:10.1159/000177172

出版商:S. Karger AG    

年代:1986

数据来源: Karger

ISSN:0250-6807    

DOI:10.1159/000177232

出版商:S. Karger AG    

年代:1986

数据来源: Karger

摘要:

The daily intake of vitamin B1; B2, B6, PP, C, A, D and E was investigated in 297 adult subjects, undergoing a check-up examination in a Health Center in Burgundy, by the 7-day self-recorded prospective protocol, to determine the prevalence of vitamin deficiency risks in an area of a West European Country. The daily vitamin intake was lower than the French Recommended Dietary Allowances: RDA (CNERNA, 1981). The intake was between 50 and 80% of RDA for vitamin B1 in 58%, B2 in 24%, B6 in 59%, PP in 43%, C in 21 %, A in 8%, D in 0.6%, E in 53% of the female population and for B1 in 40%, B2 in 18.5%, B6 in 59%, PP in 46%, C in 27%, A in 11 %, D in 7% and E in 47% of the male population. The daily vitamin intake was less than half of RDA vor vitamin B1 in 11 %, B2 in 0.6%, B6 in 33%, PP in 6.3%, C in 4.5%, A in 0.6%, D in 98%, E in 36% in the females and for B1 in 3%, B6 in 8.5%, PP in 3.5%, C in 5%, A in 0.7%, D in 91% and E in 9% in the males. The use of a probability analysis for estimating vitamin deficiencies showed intakes below their own requirement in 37.8% for Bb 18% for B2, 58.6% for B6, 46% for PP, 29% for C, 8.3% for A, 98% for D and 43.4% for E in the males and 62.5% for B1 20.9% for B2, 86% for B6, 46% for PP, 24 % for C, 9.2% for A, 98 % for D and 59.7 % for E in the females. Significant correlations were found between the daily vitamin intake and the caloric intake for B1] (r = 0.64), B2 (r = 0.46), B6 (r = 0.64) and PP (r = 0.62). The significantly lower caloric intake in females than in males explains a higher proportion of vitamin deficiencies for B1, B2, B6 and PP in this population. The consumption of green vegetables and fresh fruit, and, consequently, vitamin C intake, was higher in females. Although it was not possible to determine to what extent the vitamin intake deficiency contributes to an impaired biochemical vitamin status, the dietary data of this study supply sufficient information to demonstrate high prevalences of deficient vitamin status in France, particularly for B1, B6 and E.

ISSN:0250-6807    

DOI:10.1159/000177173

出版商:S. Karger AG    

年代:1986

数据来源: Karger

ISSN:0250-6807    

DOI:10.1159/000177233

出版商:S. Karger AG    

年代:1986

数据来源: Karger

摘要:

Effects of changes in dietary protein have been investigated on three mitochondrial enzymes, succinate dehydrogenase, isocitrate dehydrogenase and cytochrome oxidase. Weanling rats (21 days old ) were fed for 30 days on (a) a commercially produced diet (CPD) containing 21.0 % dietary protein and (b) a low protein-high carbohydrate diet (LPD) containing 3.47% dietary protein. Signs of protein-energy malnutrition developed in the animals having the low protein diet. The mitochondrial enzymes were assaysed. Some of the experimental rats were repleted by feeding them on a protein-rich diet for 3 weeks, and the same mitochondrial enzymes were assayed. The activity of mitochondrial cytochrome oxidase, which fell to 24% of the control values during the period of deficiency, rose to 91 % of the values for control rats during rehabilitation. The activities of succinate dehydrogenase and NAD+-isocitrate dehydrogenase fell to 75 and 73% of the control values, respectively, during depletion and rose to 83 and 88 % during repletion in line with the general rate of recovery of the malnourished rats as reflected by the changes in the body weights during repletion. These results show that mitochondrial cytochrome oxidase is very sensitive to changes in dietary protein. Its activity drops sharply with reduction in dietary protein intake and rises rapidly, outstripping the rate of general recovery on reverting to a protein-rich diet.

ISSN:0250-6807    

DOI:10.1159/000177174

出版商:S. Karger AG    

年代:1986

数据来源: Karger

摘要:

D-Pantethine-related metabolites, such as taurine, D-pantetheine, coenzyme A and D-pantothenate, activated yeast aldedehyde dehydrogenase in vitro. D-Pantethine and cysteamine hydrochloride, however, strongly inhibited the activity of this enzyme.

ISSN:0250-6807    

DOI:10.1159/000177175

出版商:S. Karger AG    

年代:1986

数据来源: Karger